The largest library in Bulgaria “SS. Cyril and Methodius”, keeps more than 7.9 million items: p books, rare editions, maps and graphics, archives, periodicals, manuscripts, electronic documents and databases, recordings etc.

The National Library works to completely possess all documents, printed editions and publications ever published in the country in Bulgarian and other languages. They are available without restrictions only onsite in The Library’s reading rooms, while readers out of Sofia and the country can take advantage of the International Library Loan Services. The National Library’s  collections are structured as follows: Collection of Slavonic and Foreign Language Manuscripts; Collection of Old Printed Books, Rare and Precious Editions; Bulgarian historical archive collection; Oriental Department collections; Maps and Graphics Collection; Official and Government Publications; Musical Collection and recordings; Archive of Bulgarian Literature; Foreign Books and Serials Collection; Reference Books; Special Collection in Librarianship.

10.12.1878 is officially accepted as the date of National Library's establishment. Though, the present building, especially designed for a library, was officially opened on 16.12.1953. The book depository is situated on eight floors, with 10 separate reading rooms. The building was among the first in the country with roof lights and slanting shutters, allowing direct sunlight into the rooms. The country's first ever "Conservation, Restoration and Preservation" Division with a laboratory started operating at the Library. At present, digitization admittedly facilitated these processes